Eventually the spherule-laden air becomes unstable and density currents form, transporting the spherules through the lower atmosphere collectively as plumes rather than individually at terminal velocity. This has implications for the depositional style and sedimentation rate of the global K-Pg boundary layer. Vertical density current formation in both incompressible (water) and compressible (air) fluids is evaluated numerically via KFIX-LPL simulations and analytically using new instability criteria. Models of density current formation due to particulate loading of water are compared to tephra fall experiments in order to validate the model instabilities.CHAPTER 5 VERTICAL DENSITY CURRENTS: IMPLICATIONS FOR SEDIMENTATION AT THE K-PG BOUNDARY 5.1 Introduction Fine ... of Mount Pinatubo yielded settling rates two to three orders of magnitude greater than the predicted Stokes law velocity (Wiesner et al., 1995). ... that rapid deposition of tephra-fall layers is due to transport through the ocean column by vertical density currents.
|Title||:||Atmospheric Interactions During Global Deposition of Chicxulub Impact Ejecta|
|Author||:||Tamara Joan Goldin|
|Publisher||:||ProQuest - 2008|